1. Field of the Invention
The present invention relates to a process gas supply unit for use in semiconductor manufacturing systems or lines, and more particularly to a flexible process gas supply unit which mainly includes a process gas supply valve, a purge valve, a check valve, a vacuum vale, a regulator, a filter, a pressure gage, etc.
2. Description of Related Art
For a semiconductor manufacturing line, there have been conventionally proposed process gas supply units for supplying process gas such as etching gas and the like. In the line, the method for batch-processing a plurality of wafers at once is being replaced by the method for processing the wafer on a one-by-one basis. Accordingly, a small-sized process gas supply unit is intensely required.
For downsizing the process gas supply unit, the applicants have proposed a process gas supply unit wherein a supply valve, a purge valve, and a vacuum valve are down mounted on module blocks which are manifolds by bolts, which is disclosed in Japanese patent publication No. 2,568,365.
FIG. 37 shows the structure of the process gas supply unit using the above-mentioned manifold and FIG. 38 shows a circuit diagram of the unit.
In the unit, as shown in FIG. 38, process gas flows into the left end and out the right end as indicated by arrows in the figure. A manual valve 1 is connected with a check valve 2 which is connected with a regulator 3. The regulator 3 is connected with an input valve 5. A pressure gage 4 is connected between the regulator 3 and the input valve 5. The input valve 5 is connected with an inlet port of the mass flow controller 8. The inlet port of the mass flow controller 8 is connected with a purge gas source through a purge valve 6 and a check valve 7.
An outlet port of the mass flow controller 8 is connected with an output valve 10 and vacuum pump which is a vacuum source through a vacuum valve 9. The output valve 10 is connected with a manual valve 11 of which an outlet port is connected with a vacuum chamber in the semiconductor manufacturing line.
Next, the embodied structure of the unit is explained with reference to FIG. 37. All of devices and components are mounted on a mounting panel D by bolts. Specifically, the manual valve 1 is fixed on the panel D with a bracket Y1. Both ends of the valve 1 are connected pipes 1a and 1b respectively and joints M. The pipe 1b and the joint M placed in the downstream side are connected with the check valve 2 that is connected with the regulator 3 through a joint M and a pipe 3a. The regulator 3 is fixed on the panel D with a bracket Y2 having the same structure as the bracket Y1.
With the right end of the regulator 3 are connected trifurcated pipes 5a and 4a through a joint M. The pressure gage 4 is connected with the trifurcated pipe 4a. The trifurcated pipe 5a is connected with a manifold Z1 through a joint M. On the manifold Z1 are attached the input valve 5 and the purge valve 6. A purge port of the manifold Z1 is connected with the check valve 7 through a pipe 6a and a joint M. The check valve 7 is connected with a purge gas source not illustrated through a joint M. The passage provided between the check vale 7 and the pipe 6a is formed in the interior of the manifold Z1.
The manifold Z1, to which a mass flow controller block N is joined, is fixed on the panel D with a plate X1. On the block N is mounted the mass flow controller 8. A right end of the mass flow controller block N is connected with a manifold Z2 having the same structure as the manifold Z1, on which the vacuum valve 9 and the output valve 10 are attached. The manifold Z2 is fixed on the panel D with a plate X2. The vacuum valve 9 is connected with a vacuum pump which is a vacuum source. The flow passage from the vacuum source is formed in the interior of the plate X2 having the same structure as the plate X1.
The manifold Z2 is connected with the manual valve 11 through a joint M and a pipe 11a. The manual valve 11 is fixed on the panel D with a bracket Y3 having the same structure as the bracket Y1. A right end of the manual valve 11 is connected with the vacuum chamber through a pipe 11b and a joint M.
The prior art process gas supply unit has the following disadvantages.
Adopting the manifold Z1 on which the input valve 5 and the purge valve 6 are integrally mounted from above by bolts, the unit could be downsized as compared with the unit wherein all devices are interconnected through pipes. However, such the downsized unit is yet insufficient from the viewpoint of a recent demand for a small-sized and integrated process gas supply unit. Concretely, the above unit has still much pipes and joints, resulting in the increase of space therefor.
On the other hand, the downsizing of the unit could be achieved by using manifolds and devices all made into blocks without using pipes and joints. However, since the components to be attached on the blocks are various such as a purge valve, a check valve, a vacuum valve, amass flow controller, a regulator, a filter, etc., the formation of passages suitable for each component in the blocks causes complication and the rise of cost.
In the case that the unit is used for standard lines for simply supplying process gas, the line can be linearly configured. If a purge line for purging the passage of the process gas unit is placed in the middle of the passage, however, the unit has to be arranged such that the purge line is directed to an end face of the block. This may result in completed flow passages in the blocks, which would become more non-general-purpose.